Covid’s Rising Again in New York. Keep the Schools Open.

(Bloomberg Opinion) -- Few pandemic decisions have become as destructively politicized as school closures. As a New Yorker article noted this week, whether schools are open depends more on a community's support for Donald Trump than on its Covid-19 infection rate.

And now a small resurgence of the virus in New York City has schools facing possible closure. An uptick this week has brought what's called the positivity rate above 3% for the last several days. Under current policy, a seven-day average over 3% will trigger school closings. It's not clear that 3% is the right cut-off for closing schools, though, or that re-closing the public schools would slow the pandemic.

The positivity rate represents the percent of positive tests among all those tested in a given time period. Epidemiologists say it's a measure that depends in part on how much testing is being done. If only the sickest people are getting tested, the rate is likely to be quite high. If lots of healthy people are added to the mix, the rates are likely to get lower.

“Any increase in percent positivity represents an increase in the probability a test is used on a person who is infected. That might happen because tests are limited and used on those with clear symptoms, or because there are known outbreaks that are being actively investigated,” says Harvard University epidemiologist William Hanage via email.

The positivity rate has in recent days gone from around 1% to around 3% in both New York City and Massachusetts, he says. “I am surmising that the High Holy Days have had an impact (we are now seeing the consequences of gatherings around Rosh Hashanah).” If that's so, this could be the beginning of the kind of rise we've typically seen one to two weeks after an event. 

Rates around the U.S. vary from less than 1% in some of the least affected areas to upwards of 15%. The World Health Organization has suggested a positivity rate of below 5% as a threshold for keeping schools open. Hanage says that percent positivity is less important than the overall number of positive cases — and that so far this remains relatively low in both Massachusetts and New York City.

The scientific evidence to date suggests that the risk of reopening schools are minimal for kids. A number of studies, including this recent meta analysis, show children are less likely than adults to get infected with the virus SARS-CoV-2. Summer day care centers and comparative looks at countries that have kept schools open suggest that keeping schools open doesn't necessarily ignite larger flare-ups in the population or among teachers.

As I learned reporting on schools over the summer, infectious disease doctors and pediatricians had started to agree that the cost of keeping young children out of school was worse than the risk of bringing them back.

Last spring, decisions to close schools were based in part on influenza outbreaks, which can be fueled by transmission among children, and can be deadly to children. What they've learned since then is that a few children who contract the virus suffer an inflammatory syndrome which affects their blood vessels, skin and organs, but it's so rare that children are more likely to suffer severe consequences or die from influenza or other respiratory infections.

As for the adults who work in schools, most schools in the U.S. are now using masks and social distancing to protect teachers from Covid-19. And all schools should avoid pressuring teachers who are at high risk due to age or pre-existing conditions to come into the classroom.

Over the summer, the National Academies for Science Engineering and Medicine released a study that came down in favor of reopening schools. It emphasized that children could suffer long-term consequences if they fall behind. The American Academy of Pediatrics issued a similar verdict.

The political landscape can make it appear that Americans are divided into people who take the disease so seriously they would mitigate it at any cost, and those who don't take it seriously at all. The reality we face is that the disease is something to take seriously, but so are the costs of all the closures and lockdowns and shutdowns, which may affect many people, especially children, for life.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Faye Flam is a Bloomberg Opinion columnist. She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science and other publications. She has a degree in geophysics from the California Institute of Technology.

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